Hodor, Hodor, Hodor, Hodor, Hodor.

Neuroscience explains why this Game of Thrones character can only say one word.

He might be fictional. But the gigantic Hodor, a character in the blockbuster Game of Thrones series, nonetheless sheds light on something very much in the realm of fact: how our ability to speak emerges from a complex ball of neurons, and how certain brain-damaged patients can lose very specific aspects of that ability.

According to George R.R. Martin, who wrote the epic books that inspired the HBO show, the 7-foot-tall Hodor could only say one word—"Hodor"—and everyone therefore tended to assume that was his name. Here's one passage about Hodor from the first novel in Martin's series:

Theon Greyjoy had once commented that Hodor did not know much, but no one could doubt that he knew his name. Old Nan had cackled like a hen when Bran told her that, and confessed that Hodor's real name was Walder. No one knew where "Hodor" had come from, she said, but when he started saying it, they started calling him by it. It was the only word he had.

Yet it's clear that Hodor can understand much more than he can say; he's able to follow instructions, anticipate who needed help, and behave in socially appropriate ways (mostly). Moreover, he says this one word in many different ways, implying very different meanings (...)